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The Soils of Bali Island and Their Agricultural Potential
Beyond its world-renowned tourism appeal, Bali Island
possesses another remarkable asset that often receives far less attention: its
extraordinary soil diversity, which plays a crucial role in determining the
island's agricultural potential. From the extensive Latosols that dominate the
lowlands to the fertile black Andosols found in the mountainous regions, each
soil type shapes the distinctive characteristics of the crops cultivated upon
it. Combined with Bali's unique agroclimatic conditions—ranging from humid,
high-rainfall areas to extremely dry regions—this diversity has given rise to
numerous agricultural production centers, including Buleleng's grapes,
Pancasari's strawberries, Tabanan's rice, and the renowned salak (snake fruit)
of Karangasem. This remarkable combination of diverse soils and climates makes
Bali not only culturally captivating but also exceptionally rich in agronomic
potential.
Soil texture refers to the relative proportion of the
three primary particle groups that make up the soil mass. Individual particles
are known as soil particles, while combinations of these particles are referred
to as soil fractions. The clay fraction consists of extremely fine particles
measuring less than 0.002 mm in diameter. The silt fraction ranges from 0.002
to 0.05 mm, whereas the sand fraction comprises particles between 0.05 and 2.0
mm in diameter. A soil mass may contain all three particle types in varying
proportions. Soil is classified as coarse-textured when sand particles
predominate and the proportions of the other fractions are sufficiently small
to be negligible. Medium-textured soils are characterized by a higher
proportion of silt particles, whereas soils dominated by clay particles are
classified as fine-textured. These three texture classes exhibit relatively
little variation over time, and because soil texture is considered a permanent
characteristic, it serves as a fundamental criterion in soil classification.
The soils of Bali Island are predominantly
medium-textured, with only limited areas exhibiting either fine or coarse
textures. Fine-textured soils are found in Nusa Dua, whereas coarse-textured
soils occur on Nusa Penida Island, which is administratively part of Klungkung
Regency.
Latosols account for approximately 44.59% of the total
land area of Bali Island and are distributed throughout Denpasar City and the
regencies of Badung, Tabanan, Jembrana, parts of Karangasem, Buleleng, and
Klungkung. Latosols are highly weathered soils that have undergone advanced
stages of soil development. They are typically red, ranging from deep red to
reddish-yellow or reddish-brown in color, with a soil pH of 5.5–6.5. These
soils generally possess fine to medium textures and a crumbly to slightly sticky
structure, with deep permeability and low to moderate natural fertility.
Regosols cover approximately 39.92% of Bali Island and
can be classified into three main types: volcanic ash Regosols, which occur
around volcanic areas; coastal sand dune Regosols, which are found along the
shoreline; and sedimentary Regosols, which develop on folded hill landscapes.
In general, Regosols contain relatively high levels of phosphorus and potassium
but are deficient in nitrogen. However, much of the phosphorus and potassium is
present in forms that are not yet available for plant uptake because they have
not undergone sufficient weathering. Consequently, these soils require organic
amendments, such as animal manure or compost, to accelerate the weathering
process and improve nutrient availability. Regosols generally have a soil pH
ranging from 6.0 to 7.0. As these soils mature, their structure and consistency
become increasingly compact, sometimes forming dense layers with limited
porosity and poor drainage capacity, thereby restricting water infiltration. In
general, Regosols have not yet developed stable soil aggregates, making them
highly susceptible to erosion. In Bali, Regosols are widely distributed across
Gianyar Regency, Bangli Regency, most of Karangasem Regency, parts of Klungkung
Regency, Buleleng Regency, and Denpasar City.
Mediterranean Soil and Its Agricultural Potential
Mediterranean soil is classified as a type of red soil
that has undergone soil formation over a long period of time. This soil is
alkaline in nature, with a pH ranging from 5.5 to 8.0. It contains hardened
calcium and iron compounds, has deep permeability, and a sticky structure.
Nevertheless, it possesses moderate to high fertility. This type of soil can be
found in Nusa Penida and Nusa Dua.
Alluvial soil is soil that is frequently or has recently
been affected by flooding, and therefore can be considered a young soil that
has not yet undergone horizontal differentiation. Because it is formed by flood
deposits, its characteristics depend greatly on the intensity, origin, and type
of materials transported by floodwaters. Consequently, its fertility is highly
dependent on the source of these deposited materials. This soil type covers
only 4.87% of Bali’s land area and is predominantly found along the western
coastal region.
Andosol soil, found around Lake Buyan, Lake Tamblingan,
and Brittan, is a type of black soil. The word "ando" originates
from the Japanese language, meaning dark or black. Andosols contain high levels
of organic matter with elevated carbon and nitrogen contents but are low in
phosphorus. They possess a high water-holding capacity, causing them to remain
saturated when covered by vegetation. This soil type is easily weathered yet
maintains a stable structure, making it easy to cultivate. Its high
permeability is attributed to the abundance of micropores.
Soil–Agroclimate Interaction
In agriculture, soil can be the primary factor
determining the suitability of a region for specific commodities. The
interaction between soil and agroclimate—which includes air temperature,
humidity, light intensity, and rainfall—creates interconnected conditions that
influence plant metabolism, ultimately leading to the formation of plant organs
such as leaves, flowers, and fruits. The products of these metabolic processes
directly affect the quality of agricultural commodities as well as the flavor
of the fruits and vegetables produced.
Soil-related factors can be modified through soil
management, fertilization, liming, and irrigation. In contrast, climatic
factors can only be modified by constructing greenhouses or plastic houses to
create a favorable microclimate around the crops. For smallholder farmers with
limited financial resources, however, greenhouse cultivation is generally not
economically feasible. The following sections describe how the interaction
between soil and agroclimate in different regions makes them suitable for cultivating
particular agricultural commodities.
Agricultural Potential of Bali’s Soils and Their
Challenges
A. Buleleng Regency
The soils of Buleleng Regency are dominated by Latosols
and Regosols. With an annual rainfall of 2,431 mm and an average temperature of
27°C, the region has excellent potential for agriculture. Around 1975, Buleleng
experienced rapid development in the production of Tejakula mandarin oranges (Tejakula
is the name of the subdistrict where these oranges were cultivated). This
expansion was driven by the outbreak of Citrus Vein Phloem Degeneration (CVPD),
which devastated citrus orchards in Java, resulting in the establishment of
approximately six million citrus trees in Buleleng. However, in 1983–1984, the
CVPD disease also spread to Bali and severely destroyed the island’s citrus
plantations. Following this outbreak, grape cultivation expanded throughout
Buleleng, and today the regency has become the principal grape-producing region
in Bali.
Grapevines are well suited to and grow optimally in areas
at elevations of 0–300 meters above sea level, with temperatures of 25–31°C,
relative humidity of 40–80%, annual rainfall of approximately 800 mm, and sandy
soils with a pH of 6.5–7.0. Based on these growing requirements, Buleleng is
well suited for grape cultivation, and the districts of Gerokgak, Seririt, and Banjar
have become the main grape-producing areas.
The main challenge faced by farmers is fungal disease
during the rainy season, which reduces fruit quality and makes locally produced
grapes less competitive with imported grapes in the market. In addition, the
lack of technology for processing grapes into grape juice, raisins, and other
value-added products remains a significant constraint. The number of
grape-processing factories is also limited, and most are owned by foreign
companies.
In the past, Buleleng was well known for its rice, which
was highly valued for its excellent taste and texture. However, with the
expansion of vineyards, rice production in Buleleng has declined, making
Buleleng rice increasingly difficult to find in the market.
Pancasari Village, located in Sukasada District, Buleleng
Regency, is a highland area on the shores of Lake Buyan that is widely renowned
for its strawberry production. However, the area also produces high-quality
highland vegetables, including cabbage, carrots, potatoes, and many others.
Strawberry (Fragaria vesca L.) grows optimally at elevations of
1,000–1,500 meters above sea level (masl), with daytime temperatures ranging
from 22–25°C, nighttime temperatures between 14–18°C, and relative humidity of
85–95%. These conditions should be supported by porous soil with a high organic
matter content and a soil pH of 5.8–6.5.
The soils surrounding Lake Buyan are black Andosols,
characterized by their porous structure and high organic matter content. The
combination of these soils with Pancasari Village's elevation of approximately
1,100 masl, daytime temperatures of 23–26°C, and nighttime temperatures of
around 18°C creates highly favorable conditions for strawberry cultivation. It
is therefore not surprising that most of the strawberries sold in supermarkets
in Denpasar originate from this area. In addition, chrysanthemums and orchids
are also cultivated here. Paphiopedilum and Cymbidium orchids,
which cannot thrive in the lowlands, flower exceptionally well under these
highland conditions and are distributed to markets throughout Bali,
particularly in Denpasar.
Buleleng Regency is also well known for its mango (Mangifera
indica L.) production. The interaction between the soil characteristics and
agroclimatic conditions in Buleleng makes the region highly suitable for mango
cultivation. During the harvest season, which extends from October to June,
with peak production occurring between November and December, Buleleng mangoes
dominate both supermarkets and traditional markets in Denpasar. Unfortunately,
farmers' knowledge of proper cultivation techniques for this commodity has not
yet reached an optimal level. If the government provides greater support for
the development of the mango agribusiness sector, Buleleng has the potential to
become one of the world's leading mango-producing regions, capable of
delivering both high-quality fruit and substantial production volumes.
B. Tabanan Regency
Tabanan Regency has medium-textured Latosol soil, an
annual rainfall of 2,723.5 mm, an average temperature of 27°C, and is the
center of rice production in Bali, producing 90% of the island's rice. Although
the area of rice fields in Bali has decreased over the past five years, this
region, with its well-organized subak irrigation system, remains highly
productive, particularly in Guama Subak in Marga District and Rejasa Subak in
Penebel District, both of which are lowland areas that are highly suitable for
rice cultivation.
Tabanan also has a highland area in Baturiti District,
which borders Pancasari Village in Sukasada District at an elevation of
approximately 1,100 meters above sea level. This area is a major production
center for highland vegetables from the Brassicaceae family, including
cauliflower, mustard greens, broccoli, cabbage, and others. These highland
vegetables, whether cultivated in Pancasari or Baturiti, face the same
challenges, namely declining quality due to plant diseases and problems with
seed supply. Only carrot seeds can be produced locally, while seeds for other
crops must be imported from other countries at high prices. Seed production,
particularly for Brassicaceae varieties, is a common challenge in Bali because
high-quality seeds can only be produced in areas that experience large
temperature fluctuations between daytime and nighttime temperatures.
With the soil and agroclimatic conditions found in
Tabanan Regency, the region is also well suited for cultivating mangosteen (Garcinia
mangostana L.). This fruit, renowned for its distinctive flavor and unique
appearance, is highly popular worldwide, making it an excellent prospect for
export as a fresh tropical fruit from Bali.
C. Jembrana Regency
Jembrana Regency is an area dominated by medium-textured
Latosol soils, with an average annual rainfall of 2,585 mm and an average
temperature of 28.4°C. However, to date, this region has not been recognized as
a producer of any particular commodity. Nevertheless, considering its soil
characteristics and agroclimatic conditions, the area is actually highly
suitable for the intercropping cultivation of maize and legumes.
D. Karangasem Regency
Karangasem Regency is well known throughout Indonesia and
even internationally as the production center of Bali salak (snake fruit). This
dry region receives only 197 mm of annual rainfall and has an average daily
temperature ranging from 27 to 50°C. Dominated by medium-textured Regosol
soils, the agroclimatic conditions of this area are highly favorable for salak
production, particularly Salacca edulis, which belongs to the Palmae
family.
Like other members of the Palmae family, snake fruit
(salak) does not require intensive fertilization. It only requires a small
amount of organic fertilizer, such as animal manure. Considering the relatively
high cost of chemical fertilizers such as nitrogen, phosphate, and potassium,
this makes salak cultivation highly profitable for farmers. From an
environmental perspective, salak cultivation also helps prevent soil
degradation that may result from the use of chemical fertilizers.
There are three main salak-producing areas in Karangasem,
namely Duda Village, Manggis, and Sibetan. Although Sibetan Village is actually
located in Sidemen District, Bali snake fruit originally came from these
villages and has now spread to other parts of Bali. The interaction between the
agroclimate and soil of a particular area is a unique factor in commodity
production, which is why Sibetan salak has a different and less desirable taste
when grown in Pekutatan, Tabanan Regency.
SOURCES:
1.The Soil of Bali Island and Potentials for Farming by
Rindang Dwiyani in Indonesian Geographical Expedition 2007, National
Coordinating Agency for Survey and Mapping.
2.Radarbali.jawapos.com
3.RRI.co.id
